GMC 1982 Light Duty Truck, Service Manual

Page: 555 / 1435

BRAKES 5-35
Fig. 5-35--Removing Caliper from the Disc
shoe to loosen it in the caliper housing.
Mark disc pad positions if pads are to be reinstalled.
Cleaning and Inspection
The shoes should be replaced when the lining is worn to
approximately 1/32" (0.80 mm) thickness over the rivet
heads. Replace shoes in axle sets.
1. Examine the inside of the caliper for evidence of fluid
leakage. If leakage is noted, the caliper should be
overhauled.
2. Wipe the inside of the caliper clean, including the
exterior of the dust boot. Check the boot for cuts,
cracks or other damage.
NOTICE:
Do not use compressed air to clean the inside
of the caliper since this may cause the dust boot to
become unseated.
3. Use a wire brush to remove any rust or corrosion from
the machined surfaces of the steering knuckle (or
support) and caliper. It is important to clean those
areas of the caliper and support that are in contact
during the sliding action of the caliper.
Installation
If original disc pads are being reinstalled, they must be
installed in original positions (as marked at removal).
1. Lubricate the caliper and steering knuckle (or support)
sliding surfaces and the support spring with Delco
Silicone Lube (or equivalent).
2. Install a NEW inboard shoe clip in the steering knuckle
or rear support. Be sure the tabs are positioned
correctly and the loop-type spring positioned away
from the rotor. Install the lower end of the inboard shoe
into the groove provided in the steering knuckle or
support (against the spring clip). Slide the upper end of
the shoe into position. Be sure the clip remains in
position.
3. Postion the outboard shoe in the caliper with the ears at
the top of the shoe over the caliper ears and the tab at
the bottom of the shoe engaged in the caliper cutout. If
assembly is difficult, a "C" clamp may be used. Be
careful not to mar the lining.
4. With both shoes installed, lift up the caliper and rest
the bottom edge of the outboard lining on the outer
edge of the brake disc to make sure there is no
clearance between the tab at the bottom of the
outboard shoe and the caliper abutment. The outboard
shoe should fit tightly in the caliper and should not
rattle.
5. Position the caliper over the brake disc, guiding the
upper caliper groove onto the mating surface of the
steering knuckel or caliper support. Position the caliper
to the lower steering knuckle (or support) sliding
surface.
NOTICE:
Make sure that the brake hose is not twisted or
kinked since damage to the brake hose could result.
6. Place the spring over the caliper support key, install the
assembly between the steering knuckle (or rear
support) and lower caliper groove. Tap into place (until
the key retaining screw can be installed) using a brass
punch and a light hammer (fig. 5-36).
7. Install the screw and torque to 12 to 18 lb. ft. (18-24
N-m). The bolt boss must fit fully into the circular
cutout in the key.
NOTICE:
See "Notice" on Page 1 of this section.
8. Reinstall the front wheel and tire assembly.
9. Add brake fluid to the master cylinder reservoir to
bring the fluid level up to within 1/4" (6 mm) of the
top.
NOTICE:
Before moving the vehicle, pump the brake
pedal several times to make sure that it is firm. Do not
move vehicle until a firm pedal is obtained. Check
master cylinder fluid level again after pumping the
brake pedal.